Animate image scale and bounds

This commit properly animates images with different aspect ratios.
By default, regular scale animator is used which scales up or down the entire ImageView.
If `animateClipBounds={true}` is specified on the **to** `SharedElementTransition`, instead of scaling the View, the actual Drawable bounds and scale is animated which prevents the image from appearing distorted during the transition.

* Add ability to set attributes of navigation bar buttons separately.

* Added ability to set button style when calling `setButtons` method.

* Add documentation.

fixes #942

* Send willAppear didAppear for initial screen

* empty commit

- compileSdkVersion 25
- buildToolsVersion "25.0.1"

Support status bar color in Modals

fixes #1034

* Support custom font in the Menu items.

* Fix check for custom font.

Add tabBarTranslucent style option in tabsStyle

This commit adds support for the following style properties:
titleBarTitleFontFamily - string, font name in assets
titleBarTitleTextCentered - boolean, default is false

* adding support for android centered title and custom font

* PR feedback

Support customize icon for left nav button in android

FadeIn ContentView and TopBar when pushing shared element screen

If the screen is pushed with `animated: false` then only TopBar is
animated in. This is a compromise until we expose means to control the
transition of each element on the screen.

Reading the docs I couldn't see a way to simply change the color of the status bar on Android. Only via https://github.com/wix/react-native-navigation/issues/571#issuecomment-267255350 I saw there was a prop to do this.

(Assuming this is Android only since iOS only allows for light or dark).

* Temporarily disable shared element screens in example app

* Fix card positioning when transitioning

* resolve rnn dep from npm

* Temporarily disable shared element screens in example app

* Fix card positioning when transitioning

* Add view manager

* Don’t update screen style on ViewPagerScreenChangedEvent

* change version to legacy

* Fix headers after rebase

* version bump

* Add image to each list item

* Basics structure is done (I think)

toElement also animates into place, even though values are completely wrong.

* Stop relying on refs to resolve fromElements

* Hide only corresponding fromElement

* Animate sharedElements back into place on screen pop

* Update example project with Dota heroes

* Initial curved animation implementation

* Stop resolving sharedElement refs

* Move getLocationOnScreen to ViewUtils

* Parse control points passed from Js

* Scale animation works

Not sure about pivot coordinates yet.

* minor update to SharedElementsTransition screen

* Minor changes to example screens

* Draw shared elements on Screen

Ignore Z order and draw shared elements directly on screen

* stuff

* Start animation after views are drawn

* f

* Animate text color

* Less allocations when animating text color

* Switch from RGB to LAB 😎

* Save and restore SpannedString

* Use correct status bar height in Android M

* Pass show and hide duration from Js

* Fix flicker when show animation starts

* Make shared elements not clickable

motivation: might be related to some native crash

* Use linear interpolation as default interpolation

* Code cleanup

* Clear SharedElements refs when screen is destroyed

* Code cleanup

* Add decelerate interpolator

* No more occasional flicker on animation start (Hopefully 🙏)

* Add FastOutSlowIn interpolator

* Animate only visible shared elements

* Clip bounds animator somewhat works

* Hope fully no more flickery images

* Add interpolator to each animator

* some work on shared element screens

* rebase fix

* fix lint

* Global bottomTabSelected event

* ios - add bottomTabSelected and bottomTabDeselected events

_lede_ is a [word](https://www.merriam-webster.com/dictionary/lede), not a spelling mistake. In case you were wondering.